Effect of ceramic reinforcements in TIG-welded Al/SiCp and Al/TiB2 composites for enhanced mechanical properties

Abstract This research determines the effect of various ceramic particles (SiCp and TiB₂) on the Tungsten Inert Gas (TIG) welding of Al/TiB₂ and Al/SiCp composites. The reinforcement concentrations of 2%, 4% and 6% were chosen for the investigation for both SiCp and TiB₂ particles, and their effect on tensile strength (TS), hardness, and microstructure was studied using appropriate instruments. The SEM microstructure confirmed the ceramic particles distribution of different composite materials. The microstructure of the welds varies depending on the composition of the Al/TiB₂ and Al/SiCp composites. XRD analysis displayed that the phase compound formed in weld metal is similar to the metal matrix composites (MMCs), indicating strong bonding between the reinforcements and the matrix. XRD analysis confirmed the retention of reinforcement phases without the formation of undesirable reaction products, indicating good metallurgical compatibility and stable interfacial bonding between the matrix and reinforcements. Addition of TiB₂ and SiCp ceramic reinforcements into the aluminum matrix significantly improved the hardness of the welded joints. The highest hardness value of 172.8 HV was obtained for the Al/SiCp composite containing 4 wt% SiCp, representing an improvement of 25.94% and 8.88% compared to the composites containing 2 wt% and 6 wt% SiCp, respectively. Which is greater than 25.94% and 8.88% compare to 2% and 6% respectively. Similarly, the Al/TiB₂ MMC containing 4% TiB₂ showed the maximum hardness value of 98.3 Hv, followed by the composites containing 2% (85.9 HV) and 6% (74.6 HV) TiB₂, respectively. Which is greater than 14.44% and 24.11% compare to 2% and 6% respectively. This result shown that the inclusion of reinforcement particles increases the hardness of the weld zone, with the optimum reinforcement being 4% of SiCp and 6% of TiB₂. The welded specimens were tested using tensile tester to determine their TS and ductility. The results revealed that the inclusion of ceramic particles increases the TS of the welds but ductility found to be deceased. The Al/SiCp MMCs with 4% displayed the highest TS of 226.7 MPa followed by those with 2% and 6% respectively. Which is increase 8.16% and 3.37% compare to 2% and 6% respectively. Similarly, the aluminium based MMCs containing 4% TiB₂ recorded the highest TS of 228.5 MPa followed by the Al/TiB₂ MMCs containing 2% and 6% TiB₂ respectively. Which is increase 11.35% and 4.77% compare to 2% and 6% respectively. However, the Al/SiCp MMCs with 4% SiCp showed relatively lower ductility of 2.9% when compared to the Al/TiB₂ MMCs with 4% TiB₂. Overall, the inclusion of ceramic reinforcements into the aluminium based MMCs improves the mechanical performance of the weldments, although the optimal composition depends on specific application requirements.